How can I etch dichroic glass?
GreySoul, Tue Mar 20 2007, 02:58AMHi all - I can't seem to google up any info on this, figured a chemical wiz might have an idea.
I have a sheet of dichroic borosilicate float glass. the coating process involves vapor deposition of metals on the glass surface to make optical bandpass filters... anyways
I need to very selectively etch small diameter holes in the dichroic layer and not affect the optical qualities of the glass below it. 2" sheet, need a 0.1" holes sorta evenly spaced...so....
I've done plenty of silkscreen PCBs and I figure I would just make a resist stencil on a screen and knock these out by the dozen (if not hundreds)
But I can't find anything that will eat the dichro off. So far I have tried 40% nitric acid, Datek pcb etching grade ferric chloride, and "Sparex" pickel which I think is weak sulphuric acid - no results.
Any suggestions?
Thanks all,
-Doug
Re: How can I etch dichroic glass?
Chris, Tue Mar 20 2007, 04:07AM
What kind of metals or compounds are deposited on the surface? Aqua regia can dissolve most metals (especially when thin or finely divided) except tantalum, iridium, and maybe a few others. You really need some good ventilation for it, of course, since the vapors contain free chlorine and nitrosyl chloride. Elemental bromine should attack any metal to some degree, but it is nasty to work with and much more difficult to find a resist material for than acids (you could use teflon, glass, or maybe some fluoroelastomer such as fluorosilicone or viton). You can extract usefully concentrated bromine electrolytically from bromide salt with a separatory funnel since it is dense and relatively insoluble, though.
If the layer is conductive, an electrolytic etch will be even more precise, faster, and use much less harsh or dangerous chemicals (at least before you power the cell up). A simple aqueous sodium chloride electrolytic etch works well on most metals but will produce chlorine gas (no problem with good ventilation though). That method is often used for etching relatively thick steel such as for pulsejet valves. More vigorous but also more toxic, would be a similar fluoride bath (though it could attack the glass too).
For the most powerful electrolytic etching, an anhydrous bath of fused (molten) chloride salt could be used. A eutetic 60/40 mix of lithium and potassium chloride melts very easily and below the strain point of even soda-lime glass. Also 60/40 calcium/sodium chloride melts at less than 600C. It can attack all metals at the anode, even iridium, at some rate or other. Similarly a fluoride bath would be even more vigorous, but far too toxic to be worthwhile, and chloride is sufficient for any metal anyway. Remember though that hot glass is conductive in such salt baths, but with a very brief exposure (maybe even a single low voltage capacitor discharge) it could work without damaging the glass to any appreciable degree (depending I guess on how high purity you need this). Also you would have minimal production of free halogen in the brief electrolysis.
Chris, Tue Mar 20 2007, 04:07AM
What kind of metals or compounds are deposited on the surface? Aqua regia can dissolve most metals (especially when thin or finely divided) except tantalum, iridium, and maybe a few others. You really need some good ventilation for it, of course, since the vapors contain free chlorine and nitrosyl chloride. Elemental bromine should attack any metal to some degree, but it is nasty to work with and much more difficult to find a resist material for than acids (you could use teflon, glass, or maybe some fluoroelastomer such as fluorosilicone or viton). You can extract usefully concentrated bromine electrolytically from bromide salt with a separatory funnel since it is dense and relatively insoluble, though.
If the layer is conductive, an electrolytic etch will be even more precise, faster, and use much less harsh or dangerous chemicals (at least before you power the cell up). A simple aqueous sodium chloride electrolytic etch works well on most metals but will produce chlorine gas (no problem with good ventilation though). That method is often used for etching relatively thick steel such as for pulsejet valves. More vigorous but also more toxic, would be a similar fluoride bath (though it could attack the glass too).
For the most powerful electrolytic etching, an anhydrous bath of fused (molten) chloride salt could be used. A eutetic 60/40 mix of lithium and potassium chloride melts very easily and below the strain point of even soda-lime glass. Also 60/40 calcium/sodium chloride melts at less than 600C. It can attack all metals at the anode, even iridium, at some rate or other. Similarly a fluoride bath would be even more vigorous, but far too toxic to be worthwhile, and chloride is sufficient for any metal anyway. Remember though that hot glass is conductive in such salt baths, but with a very brief exposure (maybe even a single low voltage capacitor discharge) it could work without damaging the glass to any appreciable degree (depending I guess on how high purity you need this). Also you would have minimal production of free halogen in the brief electrolysis.
Re: How can I etch dichroic glass?
Bored Chemist, Tue Mar 20 2007, 06:58AM
I think they will have used dielectric coatings rather than metals. Without kinowing what they are it's difficult to know how to dissolve them- particularly without damaging the glass.
Bored Chemist, Tue Mar 20 2007, 06:58AM
I think they will have used dielectric coatings rather than metals. Without kinowing what they are it's difficult to know how to dissolve them- particularly without damaging the glass.
Re: How can I etch dichroic glass?
Steve Conner, Tue Mar 20 2007, 11:52AM
Our optics whiz says those coatings are extremely tough and have to be got off mechanically.
Steve Conner, Tue Mar 20 2007, 11:52AM
Our optics whiz says those coatings are extremely tough and have to be got off mechanically.
Re: How can I etch dichroic glass?
GreySoul, Tue Mar 20 2007, 03:15PM
so some digging,...the coatings are titanium and quartz.
The quartz is probably why nothing has worked yet.\
And steve - I've seen this done before. most comanies use lasers, but before lasers were commonly available people used acids.
Also - anyone have experiance with imagon film? I have a roll, and if it would work better than silk screened resist I could use it.... just thinking aloud on that one.
-Doug
GreySoul, Tue Mar 20 2007, 03:15PM
so some digging,...the coatings are titanium and quartz.
The quartz is probably why nothing has worked yet.\
And steve - I've seen this done before. most comanies use lasers, but before lasers were commonly available people used acids.
Also - anyone have experiance with imagon film? I have a roll, and if it would work better than silk screened resist I could use it.... just thinking aloud on that one.
-Doug
Re: How can I etch dichroic glass?
Steve Conner, Tue Mar 20 2007, 03:28PM
Hmm, well if they used acid, it would probably have been HF.
Steve Conner, Tue Mar 20 2007, 03:28PM
Hmm, well if they used acid, it would probably have been HF.
Re: How can I etch dichroic glass?
Bored Chemist, Tue Mar 20 2007, 06:50PM
Titanium dioxide isn't a lot easier to get through than quartz and would have ignored the "etchants" you have tried so far. HF would work but it will mess up the sufrace of the substrate. What are you trying to do?
Bored Chemist, Tue Mar 20 2007, 06:50PM
Titanium dioxide isn't a lot easier to get through than quartz and would have ignored the "etchants" you have tried so far. HF would work but it will mess up the sufrace of the substrate. What are you trying to do?
Re: How can I etch dichroic glass?
GreySoul, Tue Mar 20 2007, 09:52PM
I'm trying to etch patterns onto dichro for an art project. the evenly spaced dots are just one facet of this - once i get a process down I';m going to expand into other patterns and such.
I'm well aware of companies that do this work, but the whole point of the project is I do it myself.
Would a weak hf solution slowly etch the material to where I could watch the process and remove the glass before it etches the udnerlying glass? Obviously the bottom and edges would have to be masked.... but could that work?
Also - my local chem supplier closed down I guess (if anyone knows anything about Albuchem, let me know) so... any reasonable source of HF? I'm pretty certain it's one of the harder acids to come by, right?
...anyways...thanks so far, and I'll keep updating progress if I make any.
-Doug
GreySoul, Tue Mar 20 2007, 09:52PM
I'm trying to etch patterns onto dichro for an art project. the evenly spaced dots are just one facet of this - once i get a process down I';m going to expand into other patterns and such.
I'm well aware of companies that do this work, but the whole point of the project is I do it myself.
Would a weak hf solution slowly etch the material to where I could watch the process and remove the glass before it etches the udnerlying glass? Obviously the bottom and edges would have to be masked.... but could that work?
Also - my local chem supplier closed down I guess (if anyone knows anything about Albuchem, let me know) so... any reasonable source of HF? I'm pretty certain it's one of the harder acids to come by, right?
...anyways...thanks so far, and I'll keep updating progress if I make any.
-Doug
Re: How can I etch dichroic glass?
Chris, Tue Mar 20 2007, 11:13PM
Chris, Tue Mar 20 2007, 11:13PM
so some digging,...the coatings are titanium and quartz.Actually the etchants you have tried would have a hard time with titanium too. Is it just titanium or titanium dioxide?
The quartz is probably why nothing has worked yet.\
Re: How can I etch dichroic glass?
Hazmatt_(The Underdog), Wed Mar 21 2007, 03:40AM
If you're trying to etch Ti or any of the same group metals, you use a mixture of Nitric and Hydroflouric Acids. It's a standard De-ox that my boss uses seldom because of the potency of the stuff. You can also use a Nitric BiFlouride mixture, it will be very corrosive to Ti, SiO2, and just about anything you can think of.
When using it will produce Nitrogen Oxides immediately as brown clouds of nasty toxic gas, so you have to do it out in the open, and hopefully with protection.
If you have any left over it will need to be stored in a poly jar of some sort because itll eat through most things.
Hazmatt_(The Underdog), Wed Mar 21 2007, 03:40AM
If you're trying to etch Ti or any of the same group metals, you use a mixture of Nitric and Hydroflouric Acids. It's a standard De-ox that my boss uses seldom because of the potency of the stuff. You can also use a Nitric BiFlouride mixture, it will be very corrosive to Ti, SiO2, and just about anything you can think of.
When using it will produce Nitrogen Oxides immediately as brown clouds of nasty toxic gas, so you have to do it out in the open, and hopefully with protection.
If you have any left over it will need to be stored in a poly jar of some sort because itll eat through most things.
Re: How can I etch dichroic glass?
GreySoul, Wed Mar 21 2007, 04:04AM
Ti or TiO2 - good question I will call the manufacturer tomarrow and find out. they think I am crazy for wanting to etch perfectly good dichro coated glass. - silly lab scientists. FWIW the coating process is done in a high temperature evacuated chamber to prevent oxides and assit in even coating - so I suspect I'm not dealing with an oxide here - but I could be very wrong.
the glass transmits cyan and reflects yellow if that helps any.
As for acids, I've never had a problem dealing with fuming nitric, but I know HF is much nastier stuff. I'd keep it tripled up in poly bottles and jars at the very least.
Problem is my nitric supplier (jewelry supplier) doesnt have HF.
Is there a basic sythesis I can do to get a decent strength HF solution?
-Doug
GreySoul, Wed Mar 21 2007, 04:04AM
Ti or TiO2 - good question I will call the manufacturer tomarrow and find out. they think I am crazy for wanting to etch perfectly good dichro coated glass. - silly lab scientists. FWIW the coating process is done in a high temperature evacuated chamber to prevent oxides and assit in even coating - so I suspect I'm not dealing with an oxide here - but I could be very wrong.
the glass transmits cyan and reflects yellow if that helps any.
As for acids, I've never had a problem dealing with fuming nitric, but I know HF is much nastier stuff. I'd keep it tripled up in poly bottles and jars at the very least.
Problem is my nitric supplier (jewelry supplier) doesnt have HF.
Is there a basic sythesis I can do to get a decent strength HF solution?
-Doug
Re: How can I etch dichroic glass?
Eric, Wed Mar 21 2007, 06:35AM
Ammonium biflouride is used for etching glass, I imagine this would work. It is a safer alternative to straight HF and is also alot easier to obtain. Of course it will etch the underlying glass too so you'd have to stop the process once the dichroic coating was gone.
Eric, Wed Mar 21 2007, 06:35AM
Ammonium biflouride is used for etching glass, I imagine this would work. It is a safer alternative to straight HF and is also alot easier to obtain. Of course it will etch the underlying glass too so you'd have to stop the process once the dichroic coating was gone.
Re: How can I etch dichroic glass?
Bored Chemist, Wed Mar 21 2007, 07:06AM
Metals ( give or take copper gold etc) reflect light whatever the wavelength and so wouldn't help much for a dichroic filter.
TiO2 has a high refractive index, SiO2 a relatively low one. Those are what you need for assembling dielectric structures as filters, reflectors etc.
It might be easier (if you are on good terms with the maker, to put a resist pattern on the glass before coating it.
Bored Chemist, Wed Mar 21 2007, 07:06AM
Metals ( give or take copper gold etc) reflect light whatever the wavelength and so wouldn't help much for a dichroic filter.
TiO2 has a high refractive index, SiO2 a relatively low one. Those are what you need for assembling dielectric structures as filters, reflectors etc.
It might be easier (if you are on good terms with the maker, to put a resist pattern on the glass before coating it.
Re: How can I etch dichroic glass?
ragnar, Wed Mar 21 2007, 10:17AM
You can purchase adhesive dichroic films for application to existing windows -- I suspect it would be easy to cut these up (with a CNC plotter, lasercutter, etc) and to then apply the stencil onto regular glass...?
ragnar, Wed Mar 21 2007, 10:17AM
You can purchase adhesive dichroic films for application to existing windows -- I suspect it would be easy to cut these up (with a CNC plotter, lasercutter, etc) and to then apply the stencil onto regular glass...?
Re: How can I etch dichroic glass?
Chris, Thu Mar 22 2007, 12:09AM
You can obtain it by thermal decomposition fluorocarbons such as R-134a refridgerant (1,1,1,2 tetrafluoroethylene) at 500C with air and steam. The HF can be condensed out after decomposition, but this all has to happen in a passivated nickel or platinum group metal plated aparattus. One of the intermittent products is fluorophosgene, which is a VERY deadly gas. The final product could be anywhere from nearly anhydrous HF (also very deadly toxic, and volatile) to very dilute solution depending on how much water you inject.
You can also obtain HF by the addition of concentrated sulfuric acid to fluoride salts. Again it will need distilled out as anhydrous HF, and require similar aparattus. Given the complexity, expense and possible dangers of either process, I can't imagine doing it unless you really need HF often and can't obtain it. It's really nasty stuff.
I would rather use a fluoride electro-etch process on titanium than hydrofluoric acid based etchants.
Very thin layers of metal are not neccessarily opaque. You are implying that even a layer a single atom thick of metal will be totally reflective and opaque to all forms of electromagnetic radiation. Many "colorless" materials, when in a thin layer, tend to transmit more red light while reflecting blue. Try it with a sheet of virgin grade teflon or polyethylene.
Chris, Thu Mar 22 2007, 12:09AM
Is there a basic sythesis I can do to get a decent strength HF solution?
You can obtain it by thermal decomposition fluorocarbons such as R-134a refridgerant (1,1,1,2 tetrafluoroethylene) at 500C with air and steam. The HF can be condensed out after decomposition, but this all has to happen in a passivated nickel or platinum group metal plated aparattus. One of the intermittent products is fluorophosgene, which is a VERY deadly gas. The final product could be anywhere from nearly anhydrous HF (also very deadly toxic, and volatile) to very dilute solution depending on how much water you inject.
You can also obtain HF by the addition of concentrated sulfuric acid to fluoride salts. Again it will need distilled out as anhydrous HF, and require similar aparattus. Given the complexity, expense and possible dangers of either process, I can't imagine doing it unless you really need HF often and can't obtain it. It's really nasty stuff.
I would rather use a fluoride electro-etch process on titanium than hydrofluoric acid based etchants.
Metals ( give or take copper gold etc) reflect light whatever the wavelength and so wouldn't help much for a dichroic filter.
Very thin layers of metal are not neccessarily opaque. You are implying that even a layer a single atom thick of metal will be totally reflective and opaque to all forms of electromagnetic radiation. Many "colorless" materials, when in a thin layer, tend to transmit more red light while reflecting blue. Try it with a sheet of virgin grade teflon or polyethylene.
Re: How can I etch dichroic glass?
Dr. Shark, Fri Mar 23 2007, 11:45AM
As BC pointed out the coating would most likely be TiO2, a metallic coating would not make sense for this application.
I have a gut feeling that both quartz and TiO are a lot more resistant to etching that the glass substrate, meaning that you would mess up the glass if you etched through the coating. Grinding a hard coating off a soft substrate would leave you with the same problem.
Are you sure there is no other way for your application?
Dr. Shark, Fri Mar 23 2007, 11:45AM
As BC pointed out the coating would most likely be TiO2, a metallic coating would not make sense for this application.
I have a gut feeling that both quartz and TiO are a lot more resistant to etching that the glass substrate, meaning that you would mess up the glass if you etched through the coating. Grinding a hard coating off a soft substrate would leave you with the same problem.
Are you sure there is no other way for your application?
Re: How can I etch dichroic glass?
GreySoul, Fri Mar 23 2007, 03:01PM
(in my best space villian voice)
I could use zee freeekin' laser beam.
no but really... I don't have a "freeekin' laser beam" capable of this.
The "dichro slide" and other applique methods are either prohibatively expensive or would burn off under the heat these tiles will be exsposed to.
I could contact the manufacturer to make a custom mask when the glass is coated but a custom set up is $$$$.
I've been told by some fellow glass workers that ammonium biflouride paste will actually work, it just takes a while and has to be washed off before it gets to the boro underneath - I think I'll try that method today.
I will let you know how it goes
-Doug
GreySoul, Fri Mar 23 2007, 03:01PM
(in my best space villian voice)
I could use zee freeekin' laser beam.
no but really... I don't have a "freeekin' laser beam" capable of this.
The "dichro slide" and other applique methods are either prohibatively expensive or would burn off under the heat these tiles will be exsposed to.
I could contact the manufacturer to make a custom mask when the glass is coated but a custom set up is $$$$.
I've been told by some fellow glass workers that ammonium biflouride paste will actually work, it just takes a while and has to be washed off before it gets to the boro underneath - I think I'll try that method today.
I will let you know how it goes
-Doug
Re: How can I etch dichroic glass?
Bored Chemist, Sat Mar 24 2007, 11:11AM
"Very thin layers of metal are not neccessarily opaque. You are implying that even a layer a single atom thick of metal will be totally reflective and opaque to all forms of electromagnetic radiation. "
Nope, I know perfectly well that you can see through gold leaf. What I'm saying is that you don't get wavelength discrimination from metals in the way that you can get from interference effects using different thicknesses of layers.
Bored Chemist, Sat Mar 24 2007, 11:11AM
"Very thin layers of metal are not neccessarily opaque. You are implying that even a layer a single atom thick of metal will be totally reflective and opaque to all forms of electromagnetic radiation. "
Nope, I know perfectly well that you can see through gold leaf. What I'm saying is that you don't get wavelength discrimination from metals in the way that you can get from interference effects using different thicknesses of layers.
Re: How can I etch dichroic glass?
GreySoul, Sat Mar 24 2007, 03:13PM
update:
Ammonium biflouride and sulphuric acid = death to dichroic layer and nothing to the underlying glass. SUCCESS!
there is a commercially made solution called "Etch bath" for doing this, but it was hard to track some down locally. Finally got some.
the dichro I am using is, according to the manufacturer, 14 alternating layers of SiO2 and TiO2 for a total thickness of 32nm
The whole idea of dichroic glass is to form an interference layer that will refelct certain wavelengths (in this case yellow) and transmit another color (greenish blue, not really cyan but close)
they accomplish this by putting on 1-2nm thick layers of metal then varying the thickness of the quartz layer and adding another later of metal.
in effect they're making an optical bandpass filter.
google CBS dichro for more info.
Anyways thank you all for your help, putting me on the Ammonium biflouride track was the key, so big thanks to Eric, i owe ya one :)
mods feel free to close the thread if you must - or let it trickle to the back pages in peace :)
-Doug
GreySoul, Sat Mar 24 2007, 03:13PM
update:
Ammonium biflouride and sulphuric acid = death to dichroic layer and nothing to the underlying glass. SUCCESS!
there is a commercially made solution called "Etch bath" for doing this, but it was hard to track some down locally. Finally got some.
the dichro I am using is, according to the manufacturer, 14 alternating layers of SiO2 and TiO2 for a total thickness of 32nm
The whole idea of dichroic glass is to form an interference layer that will refelct certain wavelengths (in this case yellow) and transmit another color (greenish blue, not really cyan but close)
they accomplish this by putting on 1-2nm thick layers of metal then varying the thickness of the quartz layer and adding another later of metal.
in effect they're making an optical bandpass filter.
google CBS dichro for more info.
Anyways thank you all for your help, putting me on the Ammonium biflouride track was the key, so big thanks to Eric, i owe ya one :)
mods feel free to close the thread if you must - or let it trickle to the back pages in peace :)
-Doug
Re: How can I etch dichroic glass?
ragnar, Sun Mar 25 2007, 02:38PM
I'm hoping you'll post some pics or artwork to the thread in due course, before it's closed =D
You've got us all excited now! Hehe
ragnar, Sun Mar 25 2007, 02:38PM
I'm hoping you'll post some pics or artwork to the thread in due course, before it's closed =D
You've got us all excited now! Hehe
Re: How can I etch dichroic glass?
GreySoul, Sun Mar 25 2007, 03:39PM
ok don't close the thread... I should have pics this evening if all goes well.
if things don't go well... can anyone suggest a resist material that this acid stuff wont disolve?
heh
=-Doug
GreySoul, Sun Mar 25 2007, 03:39PM
ok don't close the thread... I should have pics this evening if all goes well.
if things don't go well... can anyone suggest a resist material that this acid stuff wont disolve?
heh
=-Doug
Re: How can I etch dichroic glass?
Hazmatt_(The Underdog), Sun Mar 25 2007, 07:44PM
Bee's Wax
Hazmatt_(The Underdog), Sun Mar 25 2007, 07:44PM
Bee's Wax
Re: How can I etch dichroic glass?
GreySoul, Mon Mar 26 2007, 04:01AM
So... I don't have any pics worth taking, so no post today... as soon as i get to the dichro etching step I'll post.
today i spent researching resist materials. pertty much anything that will adhere to the glass will work. I tried:
Sharpie pen - worked
CA glue - worked
Elmers (PVA) glue - worked
scotch tape / PSA vinyl - worked
acrylic paint - worked
melted wax - worked (bees, parafin)
Screenprinting / fabric ink - worked
things that did NOT work:
China marker
grease pencil
wax crayon or any wax not melted to the glass
gum arabic
#1 litho crayon
things I've yet to try:
Imagon film
ulano Diazo emulsion
india ink
toner (fused)
oil paint
- I'm mostly interested in screenprinting these, or some form of positive working UV resist film, so I think I have what I need.
I ran my tests on 6" sheets of clear glass, (Bullseye Tekta 10mm clear) and while I can see the etch, it's VERY hard to photograph, and my scanner doesn't pick it up either.
Still.... this project is a go! pics soon
-Doug
GreySoul, Mon Mar 26 2007, 04:01AM
So... I don't have any pics worth taking, so no post today... as soon as i get to the dichro etching step I'll post.
today i spent researching resist materials. pertty much anything that will adhere to the glass will work. I tried:
Sharpie pen - worked
CA glue - worked
Elmers (PVA) glue - worked
scotch tape / PSA vinyl - worked
acrylic paint - worked
melted wax - worked (bees, parafin)
Screenprinting / fabric ink - worked
things that did NOT work:
China marker
grease pencil
wax crayon or any wax not melted to the glass
gum arabic
#1 litho crayon
things I've yet to try:
Imagon film
ulano Diazo emulsion
india ink
toner (fused)
oil paint
- I'm mostly interested in screenprinting these, or some form of positive working UV resist film, so I think I have what I need.
I ran my tests on 6" sheets of clear glass, (Bullseye Tekta 10mm clear) and while I can see the etch, it's VERY hard to photograph, and my scanner doesn't pick it up either.
Still.... this project is a go! pics soon
-Doug
Re: How can I etch dichroic glass?
..., Mon Mar 26 2007, 04:25AM
Looks like I am a little too late, but I would like to add that the laser to etch that stuff actually wouldn't be all that expensive
A simply ssy-1 laser off ebay (~$100) and a little PFN (~$50) and you would be able to etch anything that absorbs 1064nm. Since it is q-switched you get incredibly high peak powers (several megawatts) which can ablate just about anything, and it loves to eat optical coatings.
I think this would have been a perfect job for the cnc obliterator
Or, not having the stages laying around you could create temporary masks by printing on a OH transparency, and using that as a mask. You might have to but the toner side up (as it will explode when you fire at it), but since you are using a nice colminated beam from the laser it wouldn't really matter.
hehe, take your pick, you can play with nasty chemicals or bigass lasers
[on topic]
As to taking pics of it, can't you just take a pic of the shadow cast by in (in sunlight)?
..., Mon Mar 26 2007, 04:25AM
Looks like I am a little too late, but I would like to add that the laser to etch that stuff actually wouldn't be all that expensive
A simply ssy-1 laser off ebay (~$100) and a little PFN (~$50) and you would be able to etch anything that absorbs 1064nm. Since it is q-switched you get incredibly high peak powers (several megawatts) which can ablate just about anything, and it loves to eat optical coatings.I think this would have been a perfect job for the cnc obliterator
Or, not having the stages laying around you could create temporary masks by printing on a OH transparency, and using that as a mask. You might have to but the toner side up (as it will explode when you fire at it), but since you are using a nice colminated beam from the laser it wouldn't really matter.
hehe, take your pick, you can play with nasty chemicals or bigass lasers
[on topic]
As to taking pics of it, can't you just take a pic of the shadow cast by in (in sunlight)?
Re: How can I etch dichroic glass?
GreySoul, Tue Mar 27 2007, 04:13AM
mmm the shadow yes, good point.
Also, I'm in the process of making a CO2 laser - it's a long term project. one thing I had in mind was making a nice little xy table to burn dichro... but it's a ways off. I still have to make my tube and get it evacuated and filled (something I'm capable of doing, but too lazy to get around to it)
Still.... this printing and etching is fun :)
I coated a glass sheet today with photo emulsion, but it took too long to dry and had to leave the shop. I'll see if I can work on it tomarrow.
.... I think I'll wind up screening resist on. The film is higer res but not as cheap.
-Doug
GreySoul, Tue Mar 27 2007, 04:13AM
mmm the shadow yes, good point.
Also, I'm in the process of making a CO2 laser - it's a long term project. one thing I had in mind was making a nice little xy table to burn dichro... but it's a ways off. I still have to make my tube and get it evacuated and filled (something I'm capable of doing, but too lazy to get around to it)
Still.... this printing and etching is fun :)
I coated a glass sheet today with photo emulsion, but it took too long to dry and had to leave the shop. I'll see if I can work on it tomarrow.
.... I think I'll wind up screening resist on. The film is higer res but not as cheap.
-Doug
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